If syslog starts complaining about neighbor table overflow  then some limits need to be increased.

Current values:

grep . /proc/sys/net/ipv6/neigh/default/gc_thresh*

/proc/sys/net/ipv6/neigh/default/gc_thresh1:128
/proc/sys/net/ipv6/neigh/default/gc_thresh2:512
/proc/sys/net/ipv6/neigh/default/gc_thresh3:1024

Add to sysctl.conf

net.ipv6.neigh.default.gc_thresh1 = 512
net.ipv6.neigh.default.gc_thresh2 = 2048
net.ipv6.neigh.default.gc_thresh3 = 4096

Reload sysctl parameters

sysctl -p